[Xenomai] [pull] forge: Adjust default registry mount point

[Xenomai] [pull] forge: Adjust default registry mount point

[Jan Kiszka]

The following changes since commit c13ff82ac09f6daa94778dcd8b51902efd754f3d:

  rtnet: update at91_ether driver (2014-11-16 20:06:04 +0100)

are available in the git repository at:

  git://git.xenomai.org/xenomai-jki.git for-forge

for you to fetch changes up to d36ae28f9c0549c0af66e896711dde21ea769587:

  regd: Switch to tmpfs as default (2014-11-27 17:19:33 +0100)

----------------------------------------------------------------
Jan Kiszka (2):
      lib/copperplate: Use single source for default registry path
      regd: Switch to tmpfs as default

 doc/asciidoc/MIGRATION.adoc           | 2 +-
 doc/asciidoc/README.APPLICATIONS.adoc | 6 +++---
 doc/asciidoc/README.INSTALL.adoc      | 4 ++--
 lib/copperplate/init.c                | 4 ++--
 lib/copperplate/internal.h            | 3 +++
 lib/copperplate/regd/regd.c           | 4 +---
 6 files changed, 12 insertions(+), 11 deletions(-)

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Gilles Chanteperdrix]

On Thu, Nov 27, 2014 at 05:25:59PM +0100, Jan Kiszka wrote:
> The following changes since commit c13ff82ac09f6daa94778dcd8b51902efd754f3d:
> 
>   rtnet: update at91_ether driver (2014-11-16 20:06:04 +0100)
> 
> are available in the git repository at:
> 
>   git://git.xenomai.org/xenomai-jki.git for-forge
> 
> for you to fetch changes up to d36ae28f9c0549c0af66e896711dde21ea769587:
> 
>   regd: Switch to tmpfs as default (2014-11-27 17:19:33 +0100)

According to the filesystem hierarchy standard, /mnt is the standard
place for "temporarily mounted filesystems".

http://en.wikipedia.org/wiki/Filesystem_Hierarchy_Standard

/run is a deviation to the standard, and does not seem to be
indicated as a mount point (though debian mounts things there).

The standard equivalent of /run would be /var/run.

But why do we need to change that globally, is not this configurable?

-- 
					    Gilles.

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Jan Kiszka]

On 2014-11-27 19:18, Gilles Chanteperdrix wrote:
> On Thu, Nov 27, 2014 at 05:25:59PM +0100, Jan Kiszka wrote:
>> The following changes since commit c13ff82ac09f6daa94778dcd8b51902efd754f3d:
>>
>>   rtnet: update at91_ether driver (2014-11-16 20:06:04 +0100)
>>
>> are available in the git repository at:
>>
>>   git://git.xenomai.org/xenomai-jki.git for-forge
>>
>> for you to fetch changes up to d36ae28f9c0549c0af66e896711dde21ea769587:
>>
>>   regd: Switch to tmpfs as default (2014-11-27 17:19:33 +0100)
> 
> According to the filesystem hierarchy standard, /mnt is the standard
> place for "temporarily mounted filesystems".
> 
> http://en.wikipedia.org/wiki/Filesystem_Hierarchy_Standard

Right, another reason to NOT mess around with it: if something was
temporarily mounted there, we will create the mountpoint inside that
filesystem with unforeseeable side effects.

> 
> /run is a deviation to the standard, and does not seem to be
> indicated as a mount point (though debian mounts things there).

"Modern" distros do, according to that article, so I suppose the
majority. It's about to become standard.

> 
> The standard equivalent of /run would be /var/run.
> 
> But why do we need to change that globally, is not this configurable?

We must stop writing to potentially read-only and/or non-local
directories. If it's /run or /var/run, I don't care too much.

Jan

-- 
Siemens AG, Corporate Technology, CT RTC ITP SES-DE
Corporate Competence Center Embedded Linux

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Gilles Chanteperdrix]

On Thu, Nov 27, 2014 at 07:51:27PM +0100, Jan Kiszka wrote:
> On 2014-11-27 19:18, Gilles Chanteperdrix wrote:
> > On Thu, Nov 27, 2014 at 05:25:59PM +0100, Jan Kiszka wrote:
> >> The following changes since commit c13ff82ac09f6daa94778dcd8b51902efd754f3d:
> >>
> >>   rtnet: update at91_ether driver (2014-11-16 20:06:04 +0100)
> >>
> >> are available in the git repository at:
> >>
> >>   git://git.xenomai.org/xenomai-jki.git for-forge
> >>
> >> for you to fetch changes up to d36ae28f9c0549c0af66e896711dde21ea769587:
> >>
> >>   regd: Switch to tmpfs as default (2014-11-27 17:19:33 +0100)
> > 
> > According to the filesystem hierarchy standard, /mnt is the standard
> > place for "temporarily mounted filesystems".
> > 
> > http://en.wikipedia.org/wiki/Filesystem_Hierarchy_Standard
> 
> Right, another reason to NOT mess around with it: if something was
> temporarily mounted there, we will create the mountpoint inside that
> filesystem with unforeseeable side effects.

Note the plural: filesystemS
It is very very very common to have multiple directories in /mnt and
mount filesytems in there.

> 
> > 
> > /run is a deviation to the standard, and does not seem to be
> > indicated as a mount point (though debian mounts things there).
> 
> "Modern" distros do, according to that article, so I suppose the
> majority. It's about to become standard.
> 
> > 
> > The standard equivalent of /run would be /var/run.
> > 
> > But why do we need to change that globally, is not this configurable?
> 
> We must stop writing to potentially read-only and/or non-local
> directories. If it's /run or /var/run, I don't care too much.

Your change currently breaks Xenomai with the tool I, Philippe and
Jorge are using to test xenomai on the platforms I have at home. So,
there better be a good reason, and that does not look like one. If
you want mnt to be a tmpfs, then make it one, who is stopping you
from doing it ?

-- 
					    Gilles.

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Lennart Sorensen]

On Thu, Nov 27, 2014 at 07:51:27PM +0100, Jan Kiszka wrote:
> On 2014-11-27 19:18, Gilles Chanteperdrix wrote:
> > According to the filesystem hierarchy standard, /mnt is the standard
> > place for "temporarily mounted filesystems".
> > 
> > http://en.wikipedia.org/wiki/Filesystem_Hierarchy_Standard
> 
> Right, another reason to NOT mess around with it: if something was
> temporarily mounted there, we will create the mountpoint inside that
> filesystem with unforeseeable side effects.

I always read that as "temporarily mounted there by the admin or some
other human".  Certainly not automatic mounts by software.  There is a
reason /media and such exists on many distributins.

-- 
Len Sorensen

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Jan Kiszka]

On 2014-11-27 19:56, Gilles Chanteperdrix wrote:
> On Thu, Nov 27, 2014 at 07:51:27PM +0100, Jan Kiszka wrote:
>> On 2014-11-27 19:18, Gilles Chanteperdrix wrote:
>>> On Thu, Nov 27, 2014 at 05:25:59PM +0100, Jan Kiszka wrote:
>>>> The following changes since commit c13ff82ac09f6daa94778dcd8b51902efd754f3d:
>>>>
>>>>   rtnet: update at91_ether driver (2014-11-16 20:06:04 +0100)
>>>>
>>>> are available in the git repository at:
>>>>
>>>>   git://git.xenomai.org/xenomai-jki.git for-forge
>>>>
>>>> for you to fetch changes up to d36ae28f9c0549c0af66e896711dde21ea769587:
>>>>
>>>>   regd: Switch to tmpfs as default (2014-11-27 17:19:33 +0100)
>>>
>>> According to the filesystem hierarchy standard, /mnt is the standard
>>> place for "temporarily mounted filesystems".
>>>
>>> http://en.wikipedia.org/wiki/Filesystem_Hierarchy_Standard
>>
>> Right, another reason to NOT mess around with it: if something was
>> temporarily mounted there, we will create the mountpoint inside that
>> filesystem with unforeseeable side effects.
> 
> Note the plural: filesystemS
> It is very very very common to have multiple directories in /mnt and
> mount filesytems in there.
> 
>>
>>>
>>> /run is a deviation to the standard, and does not seem to be
>>> indicated as a mount point (though debian mounts things there).
>>
>> "Modern" distros do, according to that article, so I suppose the
>> majority. It's about to become standard.
>>
>>>
>>> The standard equivalent of /run would be /var/run.
>>>
>>> But why do we need to change that globally, is not this configurable?
>>
>> We must stop writing to potentially read-only and/or non-local
>> directories. If it's /run or /var/run, I don't care too much.
> 
> Your change currently breaks Xenomai with the tool I, Philippe and
> Jorge are using to test xenomai on the platforms I have at home. So,
> there better be a good reason, and that does not look like one. If
> you want mnt to be a tmpfs, then make it one, who is stopping you
> from doing it ?

/mnt existed before Xenomai 3 came around, so the latter has to accept
the rules, not the former. We must fix this default behaviour before
release.

Again, if /var/run is preferred, I'll change the commit, but /mnt is an
absolute no-go.

Jan

-- 
Siemens AG, Corporate Technology, CT RTC ITP SES-DE
Corporate Competence Center Embedded Linux

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Gilles Chanteperdrix]

On Thu, Nov 27, 2014 at 02:14:38PM -0500, Lennart Sorensen wrote:
> On Thu, Nov 27, 2014 at 07:51:27PM +0100, Jan Kiszka wrote:
> > On 2014-11-27 19:18, Gilles Chanteperdrix wrote:
> > > According to the filesystem hierarchy standard, /mnt is the standard
> > > place for "temporarily mounted filesystems".
> > > 
> > > http://en.wikipedia.org/wiki/Filesystem_Hierarchy_Standard
> > 
> > Right, another reason to NOT mess around with it: if something was
> > temporarily mounted there, we will create the mountpoint inside that
> > filesystem with unforeseeable side effects.
> 
> I always read that as "temporarily mounted there by the admin or some
> other human".  Certainly not automatic mounts by software.  There is a
> reason /media and such exists on many distributins.

I would not venture an "always", autofs for instance, used to mount
things under /mnt. and /media has not always existed either, we used
/mnt/cdrom.

-- 
					    Gilles.

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Jan Kiszka]

On 2014-11-27 21:34, Gilles Chanteperdrix wrote:
> On Thu, Nov 27, 2014 at 02:14:38PM -0500, Lennart Sorensen wrote:
>> On Thu, Nov 27, 2014 at 07:51:27PM +0100, Jan Kiszka wrote:
>>> On 2014-11-27 19:18, Gilles Chanteperdrix wrote:
>>>> According to the filesystem hierarchy standard, /mnt is the standard
>>>> place for "temporarily mounted filesystems".
>>>>
>>>> http://en.wikipedia.org/wiki/Filesystem_Hierarchy_Standard
>>>
>>> Right, another reason to NOT mess around with it: if something was
>>> temporarily mounted there, we will create the mountpoint inside that
>>> filesystem with unforeseeable side effects.
>>
>> I always read that as "temporarily mounted there by the admin or some
>> other human".  Certainly not automatic mounts by software.  There is a
>> reason /media and such exists on many distributins.
> 
> I would not venture an "always", autofs for instance, used to mount
> things under /mnt. and /media has not always existed either, we used
> /mnt/cdrom.

FHS on /mnt purpose:

"This directory is provided so that the system administrator may
temporarily mount a filesystem as needed. The content of this directory
is a local issue and should not affect the manner in which any program
is run."

I think this makes it crystal clear that Xenomai is not supposed to
touch it.

Jan

-- 
Siemens AG, Corporate Technology, CT RTC ITP SES-DE
Corporate Competence Center Embedded Linux

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Lennart Sorensen]

On Thu, Nov 27, 2014 at 09:34:00PM +0100, Gilles Chanteperdrix wrote:
> I would not venture an "always", autofs for instance, used to mount
> things under /mnt. and /media has not always existed either, we used
> /mnt/cdrom.

Debian never touched /mnt in my experience, it used /cdrom.

So as far as I am concerned, /mnt is _mine_, and software does not get to
do stuff in there.

-- 
Len Sorensen

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Lennart Sorensen]

On Thu, Nov 27, 2014 at 09:43:34PM +0100, Jan Kiszka wrote:
> FHS on /mnt purpose:
> 
> "This directory is provided so that the system administrator may
> temporarily mount a filesystem as needed. The content of this directory
> is a local issue and should not affect the manner in which any program
> is run."
> 
> I think this makes it crystal clear that Xenomai is not supposed to
> touch it.

Absolutely.  It is how I have always used it and will continue to do so.

-- 
Len Sorensen

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Gilles Chanteperdrix]

On Thu, Nov 27, 2014 at 04:47:48PM -0500, Lennart Sorensen wrote:
> On Thu, Nov 27, 2014 at 09:34:00PM +0100, Gilles Chanteperdrix wrote:
> > I would not venture an "always", autofs for instance, used to mount
> > things under /mnt. and /media has not always existed either, we used
> > /mnt/cdrom.
> 
> Debian never touched /mnt in my experience, it used /cdrom.

Again, I would not use such definite words as "always" and "never".
I am almost sure the debian autofs package used mount points under
/mnt around woody. I can not seem to find the the .deb in the debian
archive, to check and have better things to do.


> 
> So as far as I am concerned, /mnt is _mine_, and software does not get to
> do stuff in there.

Xenomai is software that _you_ decide to run. So, if it creates
something under /mnt, it is still your doing.

-- 
					    Gilles.

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Gilles Chanteperdrix]

On Thu, Nov 27, 2014 at 09:43:34PM +0100, Jan Kiszka wrote:
> On 2014-11-27 21:34, Gilles Chanteperdrix wrote:
> > On Thu, Nov 27, 2014 at 02:14:38PM -0500, Lennart Sorensen wrote:
> >> On Thu, Nov 27, 2014 at 07:51:27PM +0100, Jan Kiszka wrote:
> >>> On 2014-11-27 19:18, Gilles Chanteperdrix wrote:
> >>>> According to the filesystem hierarchy standard, /mnt is the standard
> >>>> place for "temporarily mounted filesystems".
> >>>>
> >>>> http://en.wikipedia.org/wiki/Filesystem_Hierarchy_Standard
> >>>
> >>> Right, another reason to NOT mess around with it: if something was
> >>> temporarily mounted there, we will create the mountpoint inside that
> >>> filesystem with unforeseeable side effects.
> >>
> >> I always read that as "temporarily mounted there by the admin or some
> >> other human".  Certainly not automatic mounts by software.  There is a
> >> reason /media and such exists on many distributins.
> > 
> > I would not venture an "always", autofs for instance, used to mount
> > things under /mnt. and /media has not always existed either, we used
> > /mnt/cdrom.
> 
> FHS on /mnt purpose:
> 
> "This directory is provided so that the system administrator may
> temporarily mount a filesystem as needed. The content of this directory
> is a local issue and should not affect the manner in which any program
> is run."
> 
> I think this makes it crystal clear that Xenomai is not supposed to
> touch it.

Extract from:
http://www.tldp.org/LDP/Linux-Filesystem-Hierarchy/html/mnt.html

This is a generic mount point under which you mount your filesystems
or devices. Mounting is the process by which you make a filesystem
available to the system. After mounting your files will be
accessible under the mount-point. This directory usually contains
mount points or sub-directories where you mount your floppy and your
CD. You can also create additional mount-points here if you wish.
Standard mount points would include /mnt/cdrom and /mnt/floppy.
There is no limitation to creating a mount-point anywhere on your
system but by convention and for sheer practicality do not litter
your file system with mount-points. It should be noted that some
distributions like Debian allocate /floppy and /cdrom as mount
points while Redhat and Mandrake puts them in /mnt/floppy and
/mnt/cdrom respectively.

However, it should be noted that as of FSSTND version 2.3 the
purpose of this directory has changed.


  This directory is provided so that the system administrator may temporarily
  mount a filesystem as needed. The content of this directory is a local issue
  and should not affect the manner in which any program is run.

  This directory must not be used by installation programs: a suitable temporary
  directory not in use by the system must be used instead.
  

So, at the very least, /mnt used to be the generic point used to
mount filesystems, I was not dreaming. And in fact, checking the
wikipedia article, I do not see any other directory in the "new"
standard that can be used as a place where to mount things, to fill
the role that /mnt used to have.

Unfortunately, I can not access:
http://www.pathname.com/fhs/
http://www.pathname.com/fhs/pub/fhs-2.3.html

To check the standard itself (connection times out).

-- 
					    Gilles.

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Gilles Chanteperdrix]

On Thu, Nov 27, 2014 at 09:43:34PM +0100, Jan Kiszka wrote:
> On 2014-11-27 21:34, Gilles Chanteperdrix wrote:
> > On Thu, Nov 27, 2014 at 02:14:38PM -0500, Lennart Sorensen wrote:
> >> On Thu, Nov 27, 2014 at 07:51:27PM +0100, Jan Kiszka wrote:
> >>> On 2014-11-27 19:18, Gilles Chanteperdrix wrote:
> >>>> According to the filesystem hierarchy standard, /mnt is the standard
> >>>> place for "temporarily mounted filesystems".
> >>>>
> >>>> http://en.wikipedia.org/wiki/Filesystem_Hierarchy_Standard
> >>>
> >>> Right, another reason to NOT mess around with it: if something was
> >>> temporarily mounted there, we will create the mountpoint inside that
> >>> filesystem with unforeseeable side effects.
> >>
> >> I always read that as "temporarily mounted there by the admin or some
> >> other human".  Certainly not automatic mounts by software.  There is a
> >> reason /media and such exists on many distributins.
> > 
> > I would not venture an "always", autofs for instance, used to mount
> > things under /mnt. and /media has not always existed either, we used
> > /mnt/cdrom.
> 
> FHS on /mnt purpose:
> 
> "This directory is provided so that the system administrator may
> temporarily mount a filesystem as needed. The content of this directory
> is a local issue and should not affect the manner in which any program
> is run."
> 
> I think this makes it crystal clear that Xenomai is not supposed to
> touch it.

Just to add another argument. I just asked a friend who is a
professional sysadmin. He creates directory under /mnt and mount
things under these directories. So, I am not sure the standard is
even applied by the people who should use it.

If you read on the last site I sent, under the /media article: 

Amid much controversy and consternation on the part of system and
network administrators a directory containing mount points for
removable media has now been created. Funnily enough, it has been
named /media.

Are you sure, 100% sure, that every Xenomai user expects to be able
to use /mnt as a mount point? Or that they will create directories
under /mnt like everybody has been doing since Linux exists?

-- 
					    Gilles.

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Jan Kiszka]

On 2014-11-28 00:15, Gilles Chanteperdrix wrote:
> On Thu, Nov 27, 2014 at 09:43:34PM +0100, Jan Kiszka wrote:
>> On 2014-11-27 21:34, Gilles Chanteperdrix wrote:
>>> On Thu, Nov 27, 2014 at 02:14:38PM -0500, Lennart Sorensen wrote:
>>>> On Thu, Nov 27, 2014 at 07:51:27PM +0100, Jan Kiszka wrote:
>>>>> On 2014-11-27 19:18, Gilles Chanteperdrix wrote:
>>>>>> According to the filesystem hierarchy standard, /mnt is the standard
>>>>>> place for "temporarily mounted filesystems".
>>>>>>
>>>>>> http://en.wikipedia.org/wiki/Filesystem_Hierarchy_Standard
>>>>>
>>>>> Right, another reason to NOT mess around with it: if something was
>>>>> temporarily mounted there, we will create the mountpoint inside that
>>>>> filesystem with unforeseeable side effects.
>>>>
>>>> I always read that as "temporarily mounted there by the admin or some
>>>> other human".  Certainly not automatic mounts by software.  There is a
>>>> reason /media and such exists on many distributins.
>>>
>>> I would not venture an "always", autofs for instance, used to mount
>>> things under /mnt. and /media has not always existed either, we used
>>> /mnt/cdrom.
>>
>> FHS on /mnt purpose:
>>
>> "This directory is provided so that the system administrator may
>> temporarily mount a filesystem as needed. The content of this directory
>> is a local issue and should not affect the manner in which any program
>> is run."
>>
>> I think this makes it crystal clear that Xenomai is not supposed to
>> touch it.
> 
> Just to add another argument. I just asked a friend who is a
> professional sysadmin. He creates directory under /mnt and mount
> things under these directories. So, I am not sure the standard is
> even applied by the people who should use it.
> 
> If you read on the last site I sent, under the /media article: 
> 
> Amid much controversy and consternation on the part of system and
> network administrators a directory containing mount points for
> removable media has now been created. Funnily enough, it has been
> named /media.
> 
> Are you sure, 100% sure, that every Xenomai user expects to be able
> to use /mnt as a mount point? Or that they will create directories
> under /mnt like everybody has been doing since Linux exists?

I'm both absolutely sure that a) has to be left alone by Xenomai because
of requirements of the FHS and the way /mnt is used and b) we should try
hard to avoid creating temporary dirs in persistent filesystems.

Jan

-- 
Siemens AG, Corporate Technology, CT RTC ITP SES-DE
Corporate Competence Center Embedded Linux

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Gilles Chanteperdrix]

On Fri, Nov 28, 2014 at 10:40:27AM +0100, Jan Kiszka wrote:
> On 2014-11-28 00:15, Gilles Chanteperdrix wrote:
> > On Thu, Nov 27, 2014 at 09:43:34PM +0100, Jan Kiszka wrote:
> >> On 2014-11-27 21:34, Gilles Chanteperdrix wrote:
> >>> On Thu, Nov 27, 2014 at 02:14:38PM -0500, Lennart Sorensen wrote:
> >>>> On Thu, Nov 27, 2014 at 07:51:27PM +0100, Jan Kiszka wrote:
> >>>>> On 2014-11-27 19:18, Gilles Chanteperdrix wrote:
> >>>>>> According to the filesystem hierarchy standard, /mnt is the standard
> >>>>>> place for "temporarily mounted filesystems".
> >>>>>>
> >>>>>> http://en.wikipedia.org/wiki/Filesystem_Hierarchy_Standard
> >>>>>
> >>>>> Right, another reason to NOT mess around with it: if something was
> >>>>> temporarily mounted there, we will create the mountpoint inside that
> >>>>> filesystem with unforeseeable side effects.
> >>>>
> >>>> I always read that as "temporarily mounted there by the admin or some
> >>>> other human".  Certainly not automatic mounts by software.  There is a
> >>>> reason /media and such exists on many distributins.
> >>>
> >>> I would not venture an "always", autofs for instance, used to mount
> >>> things under /mnt. and /media has not always existed either, we used
> >>> /mnt/cdrom.
> >>
> >> FHS on /mnt purpose:
> >>
> >> "This directory is provided so that the system administrator may
> >> temporarily mount a filesystem as needed. The content of this directory
> >> is a local issue and should not affect the manner in which any program
> >> is run."
> >>
> >> I think this makes it crystal clear that Xenomai is not supposed to
> >> touch it.
> > 
> > Just to add another argument. I just asked a friend who is a
> > professional sysadmin. He creates directory under /mnt and mount
> > things under these directories. So, I am not sure the standard is
> > even applied by the people who should use it.
> > 
> > If you read on the last site I sent, under the /media article: 
> > 
> > Amid much controversy and consternation on the part of system and
> > network administrators a directory containing mount points for
> > removable media has now been created. Funnily enough, it has been
> > named /media.
> > 
> > Are you sure, 100% sure, that every Xenomai user expects to be able
> > to use /mnt as a mount point? Or that they will create directories
> > under /mnt like everybody has been doing since Linux exists?
> 
> I'm both absolutely sure that a) has to be left alone by Xenomai because
> of requirements of the FHS and the way /mnt is used and b) we should try
> hard to avoid creating temporary dirs in persistent filesystems.

This is ridiculous. Because the standard changed, and one
distribution, Debian, decided to follow the new standard, which
seems to be not widely accepted, and even controversial, you want to
impose what Debian does to everybody. The distribution I use has
mount points under /mnt. So, why following Debian and not the
distribution I use, and what sysadmin have been doing for ages?

You want the mount point to be somewhere else? Fine, put a symbolic
link.

mkdir /run/xenomai
ln -s /run/xenomai /mnt/xenomai

-- 
					    Gilles.

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Jan Kiszka]

On 2014-11-28 10:50, Gilles Chanteperdrix wrote:
> On Fri, Nov 28, 2014 at 10:40:27AM +0100, Jan Kiszka wrote:
>> On 2014-11-28 00:15, Gilles Chanteperdrix wrote:
>>> On Thu, Nov 27, 2014 at 09:43:34PM +0100, Jan Kiszka wrote:
>>>> On 2014-11-27 21:34, Gilles Chanteperdrix wrote:
>>>>> On Thu, Nov 27, 2014 at 02:14:38PM -0500, Lennart Sorensen wrote:
>>>>>> On Thu, Nov 27, 2014 at 07:51:27PM +0100, Jan Kiszka wrote:
>>>>>>> On 2014-11-27 19:18, Gilles Chanteperdrix wrote:
>>>>>>>> According to the filesystem hierarchy standard, /mnt is the standard
>>>>>>>> place for "temporarily mounted filesystems".
>>>>>>>>
>>>>>>>> http://en.wikipedia.org/wiki/Filesystem_Hierarchy_Standard
>>>>>>>
>>>>>>> Right, another reason to NOT mess around with it: if something was
>>>>>>> temporarily mounted there, we will create the mountpoint inside that
>>>>>>> filesystem with unforeseeable side effects.
>>>>>>
>>>>>> I always read that as "temporarily mounted there by the admin or some
>>>>>> other human".  Certainly not automatic mounts by software.  There is a
>>>>>> reason /media and such exists on many distributins.
>>>>>
>>>>> I would not venture an "always", autofs for instance, used to mount
>>>>> things under /mnt. and /media has not always existed either, we used
>>>>> /mnt/cdrom.
>>>>
>>>> FHS on /mnt purpose:
>>>>
>>>> "This directory is provided so that the system administrator may
>>>> temporarily mount a filesystem as needed. The content of this directory
>>>> is a local issue and should not affect the manner in which any program
>>>> is run."
>>>>
>>>> I think this makes it crystal clear that Xenomai is not supposed to
>>>> touch it.
>>>
>>> Just to add another argument. I just asked a friend who is a
>>> professional sysadmin. He creates directory under /mnt and mount
>>> things under these directories. So, I am not sure the standard is
>>> even applied by the people who should use it.
>>>
>>> If you read on the last site I sent, under the /media article: 
>>>
>>> Amid much controversy and consternation on the part of system and
>>> network administrators a directory containing mount points for
>>> removable media has now been created. Funnily enough, it has been
>>> named /media.
>>>
>>> Are you sure, 100% sure, that every Xenomai user expects to be able
>>> to use /mnt as a mount point? Or that they will create directories
>>> under /mnt like everybody has been doing since Linux exists?
>>
>> I'm both absolutely sure that a) has to be left alone by Xenomai because
>> of requirements of the FHS and the way /mnt is used and b) we should try
>> hard to avoid creating temporary dirs in persistent filesystems.
> 
> This is ridiculous. Because the standard changed, and one
> distribution, Debian, decided to follow the new standard, which
> seems to be not widely accepted, and even controversial, you want to
> impose what Debian does to everybody. The distribution I use has
> mount points under /mnt. So, why following Debian and not the
> distribution I use, and what sysadmin have been doing for ages?
> 
> You want the mount point to be somewhere else? Fine, put a symbolic
> link.
> 
> mkdir /run/xenomai
> ln -s /run/xenomai /mnt/xenomai

Again, this is not acceptible as /mnt changes all the time and exposes
various remote filesystems which will hide that link. /mnt is locally
owned, not by the system to which Xenomai belongs, please accept this.
You can still define your personal setup differently if the path is not
easily fixable there.

Jan

-- 
Siemens AG, Corporate Technology, CT RTC ITP SES-DE
Corporate Competence Center Embedded Linux

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Gilles Chanteperdrix]

On Fri, Nov 28, 2014 at 10:55:56AM +0100, Jan Kiszka wrote:
> On 2014-11-28 10:50, Gilles Chanteperdrix wrote:
> > On Fri, Nov 28, 2014 at 10:40:27AM +0100, Jan Kiszka wrote:
> >> On 2014-11-28 00:15, Gilles Chanteperdrix wrote:
> >>> On Thu, Nov 27, 2014 at 09:43:34PM +0100, Jan Kiszka wrote:
> >>>> On 2014-11-27 21:34, Gilles Chanteperdrix wrote:
> >>>>> On Thu, Nov 27, 2014 at 02:14:38PM -0500, Lennart Sorensen wrote:
> >>>>>> On Thu, Nov 27, 2014 at 07:51:27PM +0100, Jan Kiszka wrote:
> >>>>>>> On 2014-11-27 19:18, Gilles Chanteperdrix wrote:
> >>>>>>>> According to the filesystem hierarchy standard, /mnt is the standard
> >>>>>>>> place for "temporarily mounted filesystems".
> >>>>>>>>
> >>>>>>>> http://en.wikipedia.org/wiki/Filesystem_Hierarchy_Standard
> >>>>>>>
> >>>>>>> Right, another reason to NOT mess around with it: if something was
> >>>>>>> temporarily mounted there, we will create the mountpoint inside that
> >>>>>>> filesystem with unforeseeable side effects.
> >>>>>>
> >>>>>> I always read that as "temporarily mounted there by the admin or some
> >>>>>> other human".  Certainly not automatic mounts by software.  There is a
> >>>>>> reason /media and such exists on many distributins.
> >>>>>
> >>>>> I would not venture an "always", autofs for instance, used to mount
> >>>>> things under /mnt. and /media has not always existed either, we used
> >>>>> /mnt/cdrom.
> >>>>
> >>>> FHS on /mnt purpose:
> >>>>
> >>>> "This directory is provided so that the system administrator may
> >>>> temporarily mount a filesystem as needed. The content of this directory
> >>>> is a local issue and should not affect the manner in which any program
> >>>> is run."
> >>>>
> >>>> I think this makes it crystal clear that Xenomai is not supposed to
> >>>> touch it.
> >>>
> >>> Just to add another argument. I just asked a friend who is a
> >>> professional sysadmin. He creates directory under /mnt and mount
> >>> things under these directories. So, I am not sure the standard is
> >>> even applied by the people who should use it.
> >>>
> >>> If you read on the last site I sent, under the /media article: 
> >>>
> >>> Amid much controversy and consternation on the part of system and
> >>> network administrators a directory containing mount points for
> >>> removable media has now been created. Funnily enough, it has been
> >>> named /media.
> >>>
> >>> Are you sure, 100% sure, that every Xenomai user expects to be able
> >>> to use /mnt as a mount point? Or that they will create directories
> >>> under /mnt like everybody has been doing since Linux exists?
> >>
> >> I'm both absolutely sure that a) has to be left alone by Xenomai because
> >> of requirements of the FHS and the way /mnt is used and b) we should try
> >> hard to avoid creating temporary dirs in persistent filesystems.
> > 
> > This is ridiculous. Because the standard changed, and one
> > distribution, Debian, decided to follow the new standard, which
> > seems to be not widely accepted, and even controversial, you want to
> > impose what Debian does to everybody. The distribution I use has
> > mount points under /mnt. So, why following Debian and not the
> > distribution I use, and what sysadmin have been doing for ages?
> > 
> > You want the mount point to be somewhere else? Fine, put a symbolic
> > link.
> > 
> > mkdir /run/xenomai
> > ln -s /run/xenomai /mnt/xenomai
> 
> Again, this is not acceptible as /mnt changes all the time and exposes
> various remote filesystems which will hide that link.

You are missing the point. Yes, Debian does that, but not all
distribution. Other distributions do not do that.

-- 
					    Gilles.

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Gilles Chanteperdrix]

On Fri, Nov 28, 2014 at 10:55:56AM +0100, Jan Kiszka wrote:
> On 2014-11-28 10:50, Gilles Chanteperdrix wrote:
> > On Fri, Nov 28, 2014 at 10:40:27AM +0100, Jan Kiszka wrote:
> >> On 2014-11-28 00:15, Gilles Chanteperdrix wrote:
> >>> On Thu, Nov 27, 2014 at 09:43:34PM +0100, Jan Kiszka wrote:
> >>>> On 2014-11-27 21:34, Gilles Chanteperdrix wrote:
> >>>>> On Thu, Nov 27, 2014 at 02:14:38PM -0500, Lennart Sorensen wrote:
> >>>>>> On Thu, Nov 27, 2014 at 07:51:27PM +0100, Jan Kiszka wrote:
> >>>>>>> On 2014-11-27 19:18, Gilles Chanteperdrix wrote:
> >>>>>>>> According to the filesystem hierarchy standard, /mnt is the standard
> >>>>>>>> place for "temporarily mounted filesystems".
> >>>>>>>>
> >>>>>>>> http://en.wikipedia.org/wiki/Filesystem_Hierarchy_Standard
> >>>>>>>
> >>>>>>> Right, another reason to NOT mess around with it: if something was
> >>>>>>> temporarily mounted there, we will create the mountpoint inside that
> >>>>>>> filesystem with unforeseeable side effects.
> >>>>>>
> >>>>>> I always read that as "temporarily mounted there by the admin or some
> >>>>>> other human".  Certainly not automatic mounts by software.  There is a
> >>>>>> reason /media and such exists on many distributins.
> >>>>>
> >>>>> I would not venture an "always", autofs for instance, used to mount
> >>>>> things under /mnt. and /media has not always existed either, we used
> >>>>> /mnt/cdrom.
> >>>>
> >>>> FHS on /mnt purpose:
> >>>>
> >>>> "This directory is provided so that the system administrator may
> >>>> temporarily mount a filesystem as needed. The content of this directory
> >>>> is a local issue and should not affect the manner in which any program
> >>>> is run."
> >>>>
> >>>> I think this makes it crystal clear that Xenomai is not supposed to
> >>>> touch it.
> >>>
> >>> Just to add another argument. I just asked a friend who is a
> >>> professional sysadmin. He creates directory under /mnt and mount
> >>> things under these directories. So, I am not sure the standard is
> >>> even applied by the people who should use it.
> >>>
> >>> If you read on the last site I sent, under the /media article: 
> >>>
> >>> Amid much controversy and consternation on the part of system and
> >>> network administrators a directory containing mount points for
> >>> removable media has now been created. Funnily enough, it has been
> >>> named /media.
> >>>
> >>> Are you sure, 100% sure, that every Xenomai user expects to be able
> >>> to use /mnt as a mount point? Or that they will create directories
> >>> under /mnt like everybody has been doing since Linux exists?
> >>
> >> I'm both absolutely sure that a) has to be left alone by Xenomai because
> >> of requirements of the FHS and the way /mnt is used and b) we should try
> >> hard to avoid creating temporary dirs in persistent filesystems.
> > 
> > This is ridiculous. Because the standard changed, and one
> > distribution, Debian, decided to follow the new standard, which
> > seems to be not widely accepted, and even controversial, you want to
> > impose what Debian does to everybody. The distribution I use has
> > mount points under /mnt. So, why following Debian and not the
> > distribution I use, and what sysadmin have been doing for ages?
> > 
> > You want the mount point to be somewhere else? Fine, put a symbolic
> > link.
> > 
> > mkdir /run/xenomai
> > ln -s /run/xenomai /mnt/xenomai
> 
> Again, this is not acceptible as /mnt changes all the time and exposes
> various remote filesystems which will hide that link. /mnt is locally
> owned, not by the system to which Xenomai belongs, please accept this.
> You can still define your personal setup differently if the path is not
> easily fixable there.

In fact, the point is. Putting xenomai mount point under /mnt does
not even break Debian. Because of the new standard, there is little
chance for any Debian package to mount anything on /mnt or under
/mnt.

It is simply the local admin decision to decide to respect or not
respect the standard. I have been using Debian since 1997 (up to
back a few days, where I finally switched), and ALWAYS mounted
things in /mnt subdirectories. And never had any problems with any
Debian packages (and as I said, I seem to remember that some
versions of the autofs packages had their mount points under /mnt,
at any rate, the autofs mount points changed with debian versions,
so, if you had them in one place and upgrading, it would have been a
PIT to follow what Debian imposed).

The standard changes the usage of /mnt, but does not provide a
replacement. So, what we are left are choices among directories that
are not specifically made for mounting things. I do not like that
option.

So yes, when using Xenomai, the user will have to accept to not
follow the standard and create a /mnt/tmp directory for temporary
mounts. But I suspect this is an issue nobody cares about, I mean,
except you and Lennart.

-- 
					    Gilles.

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Jan Kiszka]

On 2014-11-28 10:57, Gilles Chanteperdrix wrote:
> On Fri, Nov 28, 2014 at 10:55:56AM +0100, Jan Kiszka wrote:
>> On 2014-11-28 10:50, Gilles Chanteperdrix wrote:
>>> On Fri, Nov 28, 2014 at 10:40:27AM +0100, Jan Kiszka wrote:
>>>> On 2014-11-28 00:15, Gilles Chanteperdrix wrote:
>>>>> On Thu, Nov 27, 2014 at 09:43:34PM +0100, Jan Kiszka wrote:
>>>>>> On 2014-11-27 21:34, Gilles Chanteperdrix wrote:
>>>>>>> On Thu, Nov 27, 2014 at 02:14:38PM -0500, Lennart Sorensen wrote:
>>>>>>>> On Thu, Nov 27, 2014 at 07:51:27PM +0100, Jan Kiszka wrote:
>>>>>>>>> On 2014-11-27 19:18, Gilles Chanteperdrix wrote:
>>>>>>>>>> According to the filesystem hierarchy standard, /mnt is the standard
>>>>>>>>>> place for "temporarily mounted filesystems".
>>>>>>>>>>
>>>>>>>>>> http://en.wikipedia.org/wiki/Filesystem_Hierarchy_Standard
>>>>>>>>>
>>>>>>>>> Right, another reason to NOT mess around with it: if something was
>>>>>>>>> temporarily mounted there, we will create the mountpoint inside that
>>>>>>>>> filesystem with unforeseeable side effects.
>>>>>>>>
>>>>>>>> I always read that as "temporarily mounted there by the admin or some
>>>>>>>> other human".  Certainly not automatic mounts by software.  There is a
>>>>>>>> reason /media and such exists on many distributins.
>>>>>>>
>>>>>>> I would not venture an "always", autofs for instance, used to mount
>>>>>>> things under /mnt. and /media has not always existed either, we used
>>>>>>> /mnt/cdrom.
>>>>>>
>>>>>> FHS on /mnt purpose:
>>>>>>
>>>>>> "This directory is provided so that the system administrator may
>>>>>> temporarily mount a filesystem as needed. The content of this directory
>>>>>> is a local issue and should not affect the manner in which any program
>>>>>> is run."
>>>>>>
>>>>>> I think this makes it crystal clear that Xenomai is not supposed to
>>>>>> touch it.
>>>>>
>>>>> Just to add another argument. I just asked a friend who is a
>>>>> professional sysadmin. He creates directory under /mnt and mount
>>>>> things under these directories. So, I am not sure the standard is
>>>>> even applied by the people who should use it.
>>>>>
>>>>> If you read on the last site I sent, under the /media article: 
>>>>>
>>>>> Amid much controversy and consternation on the part of system and
>>>>> network administrators a directory containing mount points for
>>>>> removable media has now been created. Funnily enough, it has been
>>>>> named /media.
>>>>>
>>>>> Are you sure, 100% sure, that every Xenomai user expects to be able
>>>>> to use /mnt as a mount point? Or that they will create directories
>>>>> under /mnt like everybody has been doing since Linux exists?
>>>>
>>>> I'm both absolutely sure that a) has to be left alone by Xenomai because
>>>> of requirements of the FHS and the way /mnt is used and b) we should try
>>>> hard to avoid creating temporary dirs in persistent filesystems.
>>>
>>> This is ridiculous. Because the standard changed, and one
>>> distribution, Debian, decided to follow the new standard, which
>>> seems to be not widely accepted, and even controversial, you want to
>>> impose what Debian does to everybody. The distribution I use has
>>> mount points under /mnt. So, why following Debian and not the
>>> distribution I use, and what sysadmin have been doing for ages?
>>>
>>> You want the mount point to be somewhere else? Fine, put a symbolic
>>> link.
>>>
>>> mkdir /run/xenomai
>>> ln -s /run/xenomai /mnt/xenomai
>>
>> Again, this is not acceptible as /mnt changes all the time and exposes
>> various remote filesystems which will hide that link.
> 
> You are missing the point. Yes, Debian does that, but not all
> distribution. Other distributions do not do that.
> 

SUSE, Ubuntu, Gentoo, Red Hat - it's already standard. But I will change
my patch to /var/run to avoid surprises with other/older distros.

Jan

-- 
Siemens AG, Corporate Technology, CT RTC ITP SES-DE
Corporate Competence Center Embedded Linux

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Gilles Chanteperdrix]

On Fri, Nov 28, 2014 at 12:50:39PM +0100, Jan Kiszka wrote:
> On 2014-11-28 10:57, Gilles Chanteperdrix wrote:
> > On Fri, Nov 28, 2014 at 10:55:56AM +0100, Jan Kiszka wrote:
> >> On 2014-11-28 10:50, Gilles Chanteperdrix wrote:
> >>> On Fri, Nov 28, 2014 at 10:40:27AM +0100, Jan Kiszka wrote:
> >>>> On 2014-11-28 00:15, Gilles Chanteperdrix wrote:
> >>>>> On Thu, Nov 27, 2014 at 09:43:34PM +0100, Jan Kiszka wrote:
> >>>>>> On 2014-11-27 21:34, Gilles Chanteperdrix wrote:
> >>>>>>> On Thu, Nov 27, 2014 at 02:14:38PM -0500, Lennart Sorensen wrote:
> >>>>>>>> On Thu, Nov 27, 2014 at 07:51:27PM +0100, Jan Kiszka wrote:
> >>>>>>>>> On 2014-11-27 19:18, Gilles Chanteperdrix wrote:
> >>>>>>>>>> According to the filesystem hierarchy standard, /mnt is the standard
> >>>>>>>>>> place for "temporarily mounted filesystems".
> >>>>>>>>>>
> >>>>>>>>>> http://en.wikipedia.org/wiki/Filesystem_Hierarchy_Standard
> >>>>>>>>>
> >>>>>>>>> Right, another reason to NOT mess around with it: if something was
> >>>>>>>>> temporarily mounted there, we will create the mountpoint inside that
> >>>>>>>>> filesystem with unforeseeable side effects.
> >>>>>>>>
> >>>>>>>> I always read that as "temporarily mounted there by the admin or some
> >>>>>>>> other human".  Certainly not automatic mounts by software.  There is a
> >>>>>>>> reason /media and such exists on many distributins.
> >>>>>>>
> >>>>>>> I would not venture an "always", autofs for instance, used to mount
> >>>>>>> things under /mnt. and /media has not always existed either, we used
> >>>>>>> /mnt/cdrom.
> >>>>>>
> >>>>>> FHS on /mnt purpose:
> >>>>>>
> >>>>>> "This directory is provided so that the system administrator may
> >>>>>> temporarily mount a filesystem as needed. The content of this directory
> >>>>>> is a local issue and should not affect the manner in which any program
> >>>>>> is run."
> >>>>>>
> >>>>>> I think this makes it crystal clear that Xenomai is not supposed to
> >>>>>> touch it.
> >>>>>
> >>>>> Just to add another argument. I just asked a friend who is a
> >>>>> professional sysadmin. He creates directory under /mnt and mount
> >>>>> things under these directories. So, I am not sure the standard is
> >>>>> even applied by the people who should use it.
> >>>>>
> >>>>> If you read on the last site I sent, under the /media article: 
> >>>>>
> >>>>> Amid much controversy and consternation on the part of system and
> >>>>> network administrators a directory containing mount points for
> >>>>> removable media has now been created. Funnily enough, it has been
> >>>>> named /media.
> >>>>>
> >>>>> Are you sure, 100% sure, that every Xenomai user expects to be able
> >>>>> to use /mnt as a mount point? Or that they will create directories
> >>>>> under /mnt like everybody has been doing since Linux exists?
> >>>>
> >>>> I'm both absolutely sure that a) has to be left alone by Xenomai because
> >>>> of requirements of the FHS and the way /mnt is used and b) we should try
> >>>> hard to avoid creating temporary dirs in persistent filesystems.
> >>>
> >>> This is ridiculous. Because the standard changed, and one
> >>> distribution, Debian, decided to follow the new standard, which
> >>> seems to be not widely accepted, and even controversial, you want to
> >>> impose what Debian does to everybody. The distribution I use has
> >>> mount points under /mnt. So, why following Debian and not the
> >>> distribution I use, and what sysadmin have been doing for ages?
> >>>
> >>> You want the mount point to be somewhere else? Fine, put a symbolic
> >>> link.
> >>>
> >>> mkdir /run/xenomai
> >>> ln -s /run/xenomai /mnt/xenomai
> >>
> >> Again, this is not acceptible as /mnt changes all the time and exposes
> >> various remote filesystems which will hide that link.
> > 
> > You are missing the point. Yes, Debian does that, but not all
> > distribution. Other distributions do not do that.
> > 
> 
> SUSE, Ubuntu, Gentoo, Red Hat - it's already standard. But I will change
> my patch to /var/run to avoid surprises with other/older distros.

Again, using /mnt/xenomai does not break any distribution following
the standard.

Let us try things another way, the possibilities we have are:
- /mnt/xenomai: a solution that used to be standard but ceased to be
with the FHS which did not provide a standard replacement, but does
not break any distribution
- /run/xenomai: a solution that relies on the existence on the /run
directory, which is not standard, but is going to be, maybe.
- /var/run/xenomai: a solution which does not violate any version of
the standard, but is not standard either, does not make clear that
the directory is a mount point (which /mnt does), breaks the
existing documentation, breaks the existing usages of Xenomai 3, and
is longer to type.

So, I really find that /mnt/xenomai is the best compromise. There is
no standard solution, at least /mnt/xenomai is a solution that used
to be standard.

-- 
					    Gilles.

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Jan Kiszka]

On 2014-11-28 12:55, Gilles Chanteperdrix wrote:
> On Fri, Nov 28, 2014 at 12:50:39PM +0100, Jan Kiszka wrote:
>> On 2014-11-28 10:57, Gilles Chanteperdrix wrote:
>>> On Fri, Nov 28, 2014 at 10:55:56AM +0100, Jan Kiszka wrote:
>>>> On 2014-11-28 10:50, Gilles Chanteperdrix wrote:
>>>>> On Fri, Nov 28, 2014 at 10:40:27AM +0100, Jan Kiszka wrote:
>>>>>> On 2014-11-28 00:15, Gilles Chanteperdrix wrote:
>>>>>>> On Thu, Nov 27, 2014 at 09:43:34PM +0100, Jan Kiszka wrote:
>>>>>>>> On 2014-11-27 21:34, Gilles Chanteperdrix wrote:
>>>>>>>>> On Thu, Nov 27, 2014 at 02:14:38PM -0500, Lennart Sorensen wrote:
>>>>>>>>>> On Thu, Nov 27, 2014 at 07:51:27PM +0100, Jan Kiszka wrote:
>>>>>>>>>>> On 2014-11-27 19:18, Gilles Chanteperdrix wrote:
>>>>>>>>>>>> According to the filesystem hierarchy standard, /mnt is the standard
>>>>>>>>>>>> place for "temporarily mounted filesystems".
>>>>>>>>>>>>
>>>>>>>>>>>> http://en.wikipedia.org/wiki/Filesystem_Hierarchy_Standard
>>>>>>>>>>>
>>>>>>>>>>> Right, another reason to NOT mess around with it: if something was
>>>>>>>>>>> temporarily mounted there, we will create the mountpoint inside that
>>>>>>>>>>> filesystem with unforeseeable side effects.
>>>>>>>>>>
>>>>>>>>>> I always read that as "temporarily mounted there by the admin or some
>>>>>>>>>> other human".  Certainly not automatic mounts by software.  There is a
>>>>>>>>>> reason /media and such exists on many distributins.
>>>>>>>>>
>>>>>>>>> I would not venture an "always", autofs for instance, used to mount
>>>>>>>>> things under /mnt. and /media has not always existed either, we used
>>>>>>>>> /mnt/cdrom.
>>>>>>>>
>>>>>>>> FHS on /mnt purpose:
>>>>>>>>
>>>>>>>> "This directory is provided so that the system administrator may
>>>>>>>> temporarily mount a filesystem as needed. The content of this directory
>>>>>>>> is a local issue and should not affect the manner in which any program
>>>>>>>> is run."
>>>>>>>>
>>>>>>>> I think this makes it crystal clear that Xenomai is not supposed to
>>>>>>>> touch it.
>>>>>>>
>>>>>>> Just to add another argument. I just asked a friend who is a
>>>>>>> professional sysadmin. He creates directory under /mnt and mount
>>>>>>> things under these directories. So, I am not sure the standard is
>>>>>>> even applied by the people who should use it.
>>>>>>>
>>>>>>> If you read on the last site I sent, under the /media article: 
>>>>>>>
>>>>>>> Amid much controversy and consternation on the part of system and
>>>>>>> network administrators a directory containing mount points for
>>>>>>> removable media has now been created. Funnily enough, it has been
>>>>>>> named /media.
>>>>>>>
>>>>>>> Are you sure, 100% sure, that every Xenomai user expects to be able
>>>>>>> to use /mnt as a mount point? Or that they will create directories
>>>>>>> under /mnt like everybody has been doing since Linux exists?
>>>>>>
>>>>>> I'm both absolutely sure that a) has to be left alone by Xenomai because
>>>>>> of requirements of the FHS and the way /mnt is used and b) we should try
>>>>>> hard to avoid creating temporary dirs in persistent filesystems.
>>>>>
>>>>> This is ridiculous. Because the standard changed, and one
>>>>> distribution, Debian, decided to follow the new standard, which
>>>>> seems to be not widely accepted, and even controversial, you want to
>>>>> impose what Debian does to everybody. The distribution I use has
>>>>> mount points under /mnt. So, why following Debian and not the
>>>>> distribution I use, and what sysadmin have been doing for ages?
>>>>>
>>>>> You want the mount point to be somewhere else? Fine, put a symbolic
>>>>> link.
>>>>>
>>>>> mkdir /run/xenomai
>>>>> ln -s /run/xenomai /mnt/xenomai
>>>>
>>>> Again, this is not acceptible as /mnt changes all the time and exposes
>>>> various remote filesystems which will hide that link.
>>>
>>> You are missing the point. Yes, Debian does that, but not all
>>> distribution. Other distributions do not do that.
>>>
>>
>> SUSE, Ubuntu, Gentoo, Red Hat - it's already standard. But I will change
>> my patch to /var/run to avoid surprises with other/older distros.
> 
> Again, using /mnt/xenomai does not break any distribution following
> the standard.
> 
> Let us try things another way, the possibilities we have are:
> - /mnt/xenomai: a solution that used to be standard but ceased to be
> with the FHS which did not provide a standard replacement, but does
> not break any distribution

I don't remember that this was ever a standard. My distro (SUSE) never
used it like this as long as I can remember (~18 year).

> - /run/xenomai: a solution that relies on the existence on the /run
> directory, which is not standard, but is going to be, maybe.
> - /var/run/xenomai: a solution which does not violate any version of
> the standard, but is not standard either, does not make clear that
> the directory is a mount point (which /mnt does), breaks the

This is how it's used in practice:

gvfsd-fuse on /var/run/user/1000/gvfs type fuse.gvfsd-fuse
(rw,nosuid,nodev,relatime,user_id=1000,group_id=100)

Just to give one example.

> existing documentation, breaks the existing usages of Xenomai 3, and
> is longer to type.
> 
> So, I really find that /mnt/xenomai is the best compromise. There is
> no standard solution, at least /mnt/xenomai is a solution that used
> to be standard.

No, it remains a current standard (FHS 2.3) *violation*, it has to be
stopped.

Jan

-- 
Siemens AG, Corporate Technology, CT RTC ITP SES-DE
Corporate Competence Center Embedded Linux

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Gilles Chanteperdrix]

On Fri, Nov 28, 2014 at 01:07:31PM +0100, Jan Kiszka wrote:
> On 2014-11-28 12:55, Gilles Chanteperdrix wrote:
> > On Fri, Nov 28, 2014 at 12:50:39PM +0100, Jan Kiszka wrote:
> >> On 2014-11-28 10:57, Gilles Chanteperdrix wrote:
> >>> On Fri, Nov 28, 2014 at 10:55:56AM +0100, Jan Kiszka wrote:
> >>>> On 2014-11-28 10:50, Gilles Chanteperdrix wrote:
> >>>>> On Fri, Nov 28, 2014 at 10:40:27AM +0100, Jan Kiszka wrote:
> >>>>>> On 2014-11-28 00:15, Gilles Chanteperdrix wrote:
> >>>>>>> On Thu, Nov 27, 2014 at 09:43:34PM +0100, Jan Kiszka wrote:
> >>>>>>>> On 2014-11-27 21:34, Gilles Chanteperdrix wrote:
> >>>>>>>>> On Thu, Nov 27, 2014 at 02:14:38PM -0500, Lennart Sorensen wrote:
> >>>>>>>>>> On Thu, Nov 27, 2014 at 07:51:27PM +0100, Jan Kiszka wrote:
> >>>>>>>>>>> On 2014-11-27 19:18, Gilles Chanteperdrix wrote:
> >>>>>>>>>>>> According to the filesystem hierarchy standard, /mnt is the standard
> >>>>>>>>>>>> place for "temporarily mounted filesystems".
> >>>>>>>>>>>>
> >>>>>>>>>>>> http://en.wikipedia.org/wiki/Filesystem_Hierarchy_Standard
> >>>>>>>>>>>
> >>>>>>>>>>> Right, another reason to NOT mess around with it: if something was
> >>>>>>>>>>> temporarily mounted there, we will create the mountpoint inside that
> >>>>>>>>>>> filesystem with unforeseeable side effects.
> >>>>>>>>>>
> >>>>>>>>>> I always read that as "temporarily mounted there by the admin or some
> >>>>>>>>>> other human".  Certainly not automatic mounts by software.  There is a
> >>>>>>>>>> reason /media and such exists on many distributins.
> >>>>>>>>>
> >>>>>>>>> I would not venture an "always", autofs for instance, used to mount
> >>>>>>>>> things under /mnt. and /media has not always existed either, we used
> >>>>>>>>> /mnt/cdrom.
> >>>>>>>>
> >>>>>>>> FHS on /mnt purpose:
> >>>>>>>>
> >>>>>>>> "This directory is provided so that the system administrator may
> >>>>>>>> temporarily mount a filesystem as needed. The content of this directory
> >>>>>>>> is a local issue and should not affect the manner in which any program
> >>>>>>>> is run."
> >>>>>>>>
> >>>>>>>> I think this makes it crystal clear that Xenomai is not supposed to
> >>>>>>>> touch it.
> >>>>>>>
> >>>>>>> Just to add another argument. I just asked a friend who is a
> >>>>>>> professional sysadmin. He creates directory under /mnt and mount
> >>>>>>> things under these directories. So, I am not sure the standard is
> >>>>>>> even applied by the people who should use it.
> >>>>>>>
> >>>>>>> If you read on the last site I sent, under the /media article: 
> >>>>>>>
> >>>>>>> Amid much controversy and consternation on the part of system and
> >>>>>>> network administrators a directory containing mount points for
> >>>>>>> removable media has now been created. Funnily enough, it has been
> >>>>>>> named /media.
> >>>>>>>
> >>>>>>> Are you sure, 100% sure, that every Xenomai user expects to be able
> >>>>>>> to use /mnt as a mount point? Or that they will create directories
> >>>>>>> under /mnt like everybody has been doing since Linux exists?
> >>>>>>
> >>>>>> I'm both absolutely sure that a) has to be left alone by Xenomai because
> >>>>>> of requirements of the FHS and the way /mnt is used and b) we should try
> >>>>>> hard to avoid creating temporary dirs in persistent filesystems.
> >>>>>
> >>>>> This is ridiculous. Because the standard changed, and one
> >>>>> distribution, Debian, decided to follow the new standard, which
> >>>>> seems to be not widely accepted, and even controversial, you want to
> >>>>> impose what Debian does to everybody. The distribution I use has
> >>>>> mount points under /mnt. So, why following Debian and not the
> >>>>> distribution I use, and what sysadmin have been doing for ages?
> >>>>>
> >>>>> You want the mount point to be somewhere else? Fine, put a symbolic
> >>>>> link.
> >>>>>
> >>>>> mkdir /run/xenomai
> >>>>> ln -s /run/xenomai /mnt/xenomai
> >>>>
> >>>> Again, this is not acceptible as /mnt changes all the time and exposes
> >>>> various remote filesystems which will hide that link.
> >>>
> >>> You are missing the point. Yes, Debian does that, but not all
> >>> distribution. Other distributions do not do that.
> >>>
> >>
> >> SUSE, Ubuntu, Gentoo, Red Hat - it's already standard. But I will change
> >> my patch to /var/run to avoid surprises with other/older distros.
> > 
> > Again, using /mnt/xenomai does not break any distribution following
> > the standard.
> > 
> > Let us try things another way, the possibilities we have are:
> > - /mnt/xenomai: a solution that used to be standard but ceased to be
> > with the FHS which did not provide a standard replacement, but does
> > not break any distribution
> 
> I don't remember that this was ever a standard. My distro (SUSE) never
> used it like this as long as I can remember (~18 year).

You have not read the link I posted it seems:
http://www.tldp.org/LDP/Linux-Filesystem-Hierarchy/html/mnt.html

> 
> > - /run/xenomai: a solution that relies on the existence on the /run
> > directory, which is not standard, but is going to be, maybe.
> > - /var/run/xenomai: a solution which does not violate any version of
> > the standard, but is not standard either, does not make clear that
> > the directory is a mount point (which /mnt does), breaks the
> 
> This is how it's used in practice:
> 
> gvfsd-fuse on /var/run/user/1000/gvfs type fuse.gvfsd-fuse
> (rw,nosuid,nodev,relatime,user_id=1000,group_id=100)
> 
> Just to give one example.
> 
> > existing documentation, breaks the existing usages of Xenomai 3, and
> > is longer to type.
> > 
> > So, I really find that /mnt/xenomai is the best compromise. There is
> > no standard solution, at least /mnt/xenomai is a solution that used
> > to be standard.
> 
> No, it remains a current standard (FHS 2.3) *violation*, it has to be
> stopped.

I do not think it is. /mnt is off limit for distributions. Fine,
xenomai can use it without any risk of breaking any distribution
then.

-- 
					    Gilles.

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Gilles Chanteperdrix]

On Fri, Nov 28, 2014 at 01:07:31PM +0100, Jan Kiszka wrote:
> On 2014-11-28 12:55, Gilles Chanteperdrix wrote:
> > On Fri, Nov 28, 2014 at 12:50:39PM +0100, Jan Kiszka wrote:
> >> On 2014-11-28 10:57, Gilles Chanteperdrix wrote:
> >>> On Fri, Nov 28, 2014 at 10:55:56AM +0100, Jan Kiszka wrote:
> >>>> On 2014-11-28 10:50, Gilles Chanteperdrix wrote:
> >>>>> On Fri, Nov 28, 2014 at 10:40:27AM +0100, Jan Kiszka wrote:
> >>>>>> On 2014-11-28 00:15, Gilles Chanteperdrix wrote:
> >>>>>>> On Thu, Nov 27, 2014 at 09:43:34PM +0100, Jan Kiszka wrote:
> >>>>>>>> On 2014-11-27 21:34, Gilles Chanteperdrix wrote:
> >>>>>>>>> On Thu, Nov 27, 2014 at 02:14:38PM -0500, Lennart Sorensen wrote:
> >>>>>>>>>> On Thu, Nov 27, 2014 at 07:51:27PM +0100, Jan Kiszka wrote:
> >>>>>>>>>>> On 2014-11-27 19:18, Gilles Chanteperdrix wrote:
> >>>>>>>>>>>> According to the filesystem hierarchy standard, /mnt is the standard
> >>>>>>>>>>>> place for "temporarily mounted filesystems".
> >>>>>>>>>>>>
> >>>>>>>>>>>> http://en.wikipedia.org/wiki/Filesystem_Hierarchy_Standard
> >>>>>>>>>>>
> >>>>>>>>>>> Right, another reason to NOT mess around with it: if something was
> >>>>>>>>>>> temporarily mounted there, we will create the mountpoint inside that
> >>>>>>>>>>> filesystem with unforeseeable side effects.
> >>>>>>>>>>
> >>>>>>>>>> I always read that as "temporarily mounted there by the admin or some
> >>>>>>>>>> other human".  Certainly not automatic mounts by software.  There is a
> >>>>>>>>>> reason /media and such exists on many distributins.
> >>>>>>>>>
> >>>>>>>>> I would not venture an "always", autofs for instance, used to mount
> >>>>>>>>> things under /mnt. and /media has not always existed either, we used
> >>>>>>>>> /mnt/cdrom.
> >>>>>>>>
> >>>>>>>> FHS on /mnt purpose:
> >>>>>>>>
> >>>>>>>> "This directory is provided so that the system administrator may
> >>>>>>>> temporarily mount a filesystem as needed. The content of this directory
> >>>>>>>> is a local issue and should not affect the manner in which any program
> >>>>>>>> is run."
> >>>>>>>>
> >>>>>>>> I think this makes it crystal clear that Xenomai is not supposed to
> >>>>>>>> touch it.
> >>>>>>>
> >>>>>>> Just to add another argument. I just asked a friend who is a
> >>>>>>> professional sysadmin. He creates directory under /mnt and mount
> >>>>>>> things under these directories. So, I am not sure the standard is
> >>>>>>> even applied by the people who should use it.
> >>>>>>>
> >>>>>>> If you read on the last site I sent, under the /media article: 
> >>>>>>>
> >>>>>>> Amid much controversy and consternation on the part of system and
> >>>>>>> network administrators a directory containing mount points for
> >>>>>>> removable media has now been created. Funnily enough, it has been
> >>>>>>> named /media.
> >>>>>>>
> >>>>>>> Are you sure, 100% sure, that every Xenomai user expects to be able
> >>>>>>> to use /mnt as a mount point? Or that they will create directories
> >>>>>>> under /mnt like everybody has been doing since Linux exists?
> >>>>>>
> >>>>>> I'm both absolutely sure that a) has to be left alone by Xenomai because
> >>>>>> of requirements of the FHS and the way /mnt is used and b) we should try
> >>>>>> hard to avoid creating temporary dirs in persistent filesystems.
> >>>>>
> >>>>> This is ridiculous. Because the standard changed, and one
> >>>>> distribution, Debian, decided to follow the new standard, which
> >>>>> seems to be not widely accepted, and even controversial, you want to
> >>>>> impose what Debian does to everybody. The distribution I use has
> >>>>> mount points under /mnt. So, why following Debian and not the
> >>>>> distribution I use, and what sysadmin have been doing for ages?
> >>>>>
> >>>>> You want the mount point to be somewhere else? Fine, put a symbolic
> >>>>> link.
> >>>>>
> >>>>> mkdir /run/xenomai
> >>>>> ln -s /run/xenomai /mnt/xenomai
> >>>>
> >>>> Again, this is not acceptible as /mnt changes all the time and exposes
> >>>> various remote filesystems which will hide that link.
> >>>
> >>> You are missing the point. Yes, Debian does that, but not all
> >>> distribution. Other distributions do not do that.
> >>>
> >>
> >> SUSE, Ubuntu, Gentoo, Red Hat - it's already standard. But I will change
> >> my patch to /var/run to avoid surprises with other/older distros.
> > 
> > Again, using /mnt/xenomai does not break any distribution following
> > the standard.
> > 
> > Let us try things another way, the possibilities we have are:
> > - /mnt/xenomai: a solution that used to be standard but ceased to be
> > with the FHS which did not provide a standard replacement, but does
> > not break any distribution
> 
> I don't remember that this was ever a standard. My distro (SUSE) never
> used it like this as long as I can remember (~18 year).
> 
> > - /run/xenomai: a solution that relies on the existence on the /run
> > directory, which is not standard, but is going to be, maybe.
> > - /var/run/xenomai: a solution which does not violate any version of
> > the standard, but is not standard either, does not make clear that
> > the directory is a mount point (which /mnt does), breaks the
> 
> This is how it's used in practice:
> 
> gvfsd-fuse on /var/run/user/1000/gvfs type fuse.gvfsd-fuse
> (rw,nosuid,nodev,relatime,user_id=1000,group_id=100)

I note that you carefully avoid quoting and answering the part of my
answer that pointed to the issues raised by your patch.

-- 
					    Gilles.

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Gilles Chanteperdrix]

On Fri, Nov 28, 2014 at 01:07:31PM +0100, Jan Kiszka wrote:
> On 2014-11-28 12:55, Gilles Chanteperdrix wrote:
> > On Fri, Nov 28, 2014 at 12:50:39PM +0100, Jan Kiszka wrote:
> >> On 2014-11-28 10:57, Gilles Chanteperdrix wrote:
> >>> On Fri, Nov 28, 2014 at 10:55:56AM +0100, Jan Kiszka wrote:
> >>>> On 2014-11-28 10:50, Gilles Chanteperdrix wrote:
> >>>>> On Fri, Nov 28, 2014 at 10:40:27AM +0100, Jan Kiszka wrote:
> >>>>>> On 2014-11-28 00:15, Gilles Chanteperdrix wrote:
> >>>>>>> On Thu, Nov 27, 2014 at 09:43:34PM +0100, Jan Kiszka wrote:
> >>>>>>>> On 2014-11-27 21:34, Gilles Chanteperdrix wrote:
> >>>>>>>>> On Thu, Nov 27, 2014 at 02:14:38PM -0500, Lennart Sorensen wrote:
> >>>>>>>>>> On Thu, Nov 27, 2014 at 07:51:27PM +0100, Jan Kiszka wrote:
> >>>>>>>>>>> On 2014-11-27 19:18, Gilles Chanteperdrix wrote:
> >>>>>>>>>>>> According to the filesystem hierarchy standard, /mnt is the standard
> >>>>>>>>>>>> place for "temporarily mounted filesystems".
> >>>>>>>>>>>>
> >>>>>>>>>>>> http://en.wikipedia.org/wiki/Filesystem_Hierarchy_Standard
> >>>>>>>>>>>
> >>>>>>>>>>> Right, another reason to NOT mess around with it: if something was
> >>>>>>>>>>> temporarily mounted there, we will create the mountpoint inside that
> >>>>>>>>>>> filesystem with unforeseeable side effects.
> >>>>>>>>>>
> >>>>>>>>>> I always read that as "temporarily mounted there by the admin or some
> >>>>>>>>>> other human".  Certainly not automatic mounts by software.  There is a
> >>>>>>>>>> reason /media and such exists on many distributins.
> >>>>>>>>>
> >>>>>>>>> I would not venture an "always", autofs for instance, used to mount
> >>>>>>>>> things under /mnt. and /media has not always existed either, we used
> >>>>>>>>> /mnt/cdrom.
> >>>>>>>>
> >>>>>>>> FHS on /mnt purpose:
> >>>>>>>>
> >>>>>>>> "This directory is provided so that the system administrator may
> >>>>>>>> temporarily mount a filesystem as needed. The content of this directory
> >>>>>>>> is a local issue and should not affect the manner in which any program
> >>>>>>>> is run."
> >>>>>>>>
> >>>>>>>> I think this makes it crystal clear that Xenomai is not supposed to
> >>>>>>>> touch it.
> >>>>>>>
> >>>>>>> Just to add another argument. I just asked a friend who is a
> >>>>>>> professional sysadmin. He creates directory under /mnt and mount
> >>>>>>> things under these directories. So, I am not sure the standard is
> >>>>>>> even applied by the people who should use it.
> >>>>>>>
> >>>>>>> If you read on the last site I sent, under the /media article: 
> >>>>>>>
> >>>>>>> Amid much controversy and consternation on the part of system and
> >>>>>>> network administrators a directory containing mount points for
> >>>>>>> removable media has now been created. Funnily enough, it has been
> >>>>>>> named /media.
> >>>>>>>
> >>>>>>> Are you sure, 100% sure, that every Xenomai user expects to be able
> >>>>>>> to use /mnt as a mount point? Or that they will create directories
> >>>>>>> under /mnt like everybody has been doing since Linux exists?
> >>>>>>
> >>>>>> I'm both absolutely sure that a) has to be left alone by Xenomai because
> >>>>>> of requirements of the FHS and the way /mnt is used and b) we should try
> >>>>>> hard to avoid creating temporary dirs in persistent filesystems.
> >>>>>
> >>>>> This is ridiculous. Because the standard changed, and one
> >>>>> distribution, Debian, decided to follow the new standard, which
> >>>>> seems to be not widely accepted, and even controversial, you want to
> >>>>> impose what Debian does to everybody. The distribution I use has
> >>>>> mount points under /mnt. So, why following Debian and not the
> >>>>> distribution I use, and what sysadmin have been doing for ages?
> >>>>>
> >>>>> You want the mount point to be somewhere else? Fine, put a symbolic
> >>>>> link.
> >>>>>
> >>>>> mkdir /run/xenomai
> >>>>> ln -s /run/xenomai /mnt/xenomai
> >>>>
> >>>> Again, this is not acceptible as /mnt changes all the time and exposes
> >>>> various remote filesystems which will hide that link.
> >>>
> >>> You are missing the point. Yes, Debian does that, but not all
> >>> distribution. Other distributions do not do that.
> >>>
> >>
> >> SUSE, Ubuntu, Gentoo, Red Hat - it's already standard. But I will change
> >> my patch to /var/run to avoid surprises with other/older distros.
> > 
> > Again, using /mnt/xenomai does not break any distribution following
> > the standard.
> > 
> > Let us try things another way, the possibilities we have are:
> > - /mnt/xenomai: a solution that used to be standard but ceased to be
> > with the FHS which did not provide a standard replacement, but does
> > not break any distribution
> 
> I don't remember that this was ever a standard. My distro (SUSE) never
> used it like this as long as I can remember (~18 year).
> 
> > - /run/xenomai: a solution that relies on the existence on the /run
> > directory, which is not standard, but is going to be, maybe.
> > - /var/run/xenomai: a solution which does not violate any version of
> > the standard, but is not standard either, does not make clear that
> > the directory is a mount point (which /mnt does), breaks the
> 
> This is how it's used in practice:
> 
> gvfsd-fuse on /var/run/user/1000/gvfs type fuse.gvfsd-fuse
> (rw,nosuid,nodev,relatime,user_id=1000,group_id=100)

It does not seem to be standard. Mine uses:
gvfsd-fuse on /home/gilles/.gvfs type fuse.gvfsd-fuse (rw,nosuid,nodev,user=gilles)

That is the problem: the FHS standard does not define an equivalent
to what /mnt used to be. So, everyone mount things wherever he
wants.

-- 
					    Gilles.

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[dietmar.schindler]

> Von: Gilles Chanteperdrix
> Gesendet: Freitag, 28. November 2014 11:16
> ...
> In fact, the point is. Putting xenomai mount point under /mnt does
> not even break Debian. Because of the new standard, there is little
> chance for any Debian package to mount anything on /mnt or under
> /mnt.
>
> It is simply the local admin decision to decide to respect or not
> respect the standard. I have been using Debian since 1997 (up to
> back a few days, where I finally switched), and ALWAYS mounted
> things in /mnt subdirectories. And never had any problems with any
> Debian packages (and as I said, I seem to remember that some
> versions of the autofs packages had their mount points under /mnt,
> at any rate, the autofs mount points changed with debian versions,
> so, if you had them in one place and upgrading, it would have been a
> PIT to follow what Debian imposed).
>
> The standard changes the usage of /mnt, but does not provide a
> replacement. So, what we are left are choices among directories that
> are not specifically made for mounting things. I do not like that
> option.
>
> So yes, when using Xenomai, the user will have to accept to not
> follow the standard and create a /mnt/tmp directory for temporary
> mounts. But I suspect this is an issue nobody cares about, I mean,
> except you and Lennart.

I don't want to add fuel to the fire, but I also care about following (even changing) standards. And I'm afraid I fail to see the problem with choosing another temporary mount point. As you cited from http://www.tldp.org/LDP/Linux-Filesystem-Hierarchy/html/mnt.html in your message on 27.11.2014 23:56:

  This directory [/mnt] must not be used by installation programs: a suitable temporary
  directory not in use by the system must be used instead.

So, wouldn't using something like "/tmp/xenomai" conform to the new standard as well as work on old systems?
--
Best regards,
Dietmar Schindler
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Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Gilles Chanteperdrix]

On Fri, Nov 28, 2014 at 12:26:32PM +0000, dietmar.schindler@manroland-web.com wrote:
> > Von: Gilles Chanteperdrix
> > Gesendet: Freitag, 28. November 2014 11:16
> > ...
> > In fact, the point is. Putting xenomai mount point under /mnt does
> > not even break Debian. Because of the new standard, there is little
> > chance for any Debian package to mount anything on /mnt or under
> > /mnt.
> >
> > It is simply the local admin decision to decide to respect or not
> > respect the standard. I have been using Debian since 1997 (up to
> > back a few days, where I finally switched), and ALWAYS mounted
> > things in /mnt subdirectories. And never had any problems with any
> > Debian packages (and as I said, I seem to remember that some
> > versions of the autofs packages had their mount points under /mnt,
> > at any rate, the autofs mount points changed with debian versions,
> > so, if you had them in one place and upgrading, it would have been a
> > PIT to follow what Debian imposed).
> >
> > The standard changes the usage of /mnt, but does not provide a
> > replacement. So, what we are left are choices among directories that
> > are not specifically made for mounting things. I do not like that
> > option.
> >
> > So yes, when using Xenomai, the user will have to accept to not
> > follow the standard and create a /mnt/tmp directory for temporary
> > mounts. But I suspect this is an issue nobody cares about, I mean,
> > except you and Lennart.
> 
> I don't want to add fuel to the fire, but I also care about
> following (even changing) standards. And I'm afraid I fail to see
> the problem with choosing another temporary mount point. 

The problem is not why not? The problem is why. A mount point was
chosen, which is not stupid, documentation and web contents were
written, people have started getting used to it. So, why changing it
now ? So from my point of view, Jan patch looks like a patch that
has been submitted without thinking to the consequences, and changes
things for bad reasons.

> As you
> cited from
> http://www.tldp.org/LDP/Linux-Filesystem-Hierarchy/html/mnt.html
> in your message on 27.11.2014 23:56:
> 
>   This directory [/mnt] must not be used by installation programs:
>   a suitable temporary directory not in use by the system must be
>   used instead.
> 
> So, wouldn't using something like "/tmp/xenomai" conform to the
> new standard as well as work on old systems?

The sentence you quote does not really apply to xenomai, since
xenomai is not an "installation program". The standard basically
says that software installed by the distribution has no business
messing with /mnt. But Xenomai is not installed by a distribution.
If distibutions want to change this directory when they make xenomai
their own package, they will apply patches, they do this all the
time, and document the difference in
/usr/share/doc/xenomai/README.Debian

-- 
					    Gilles.

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Lennart Sorensen]

On Fri, Nov 28, 2014 at 12:15:27AM +0100, Gilles Chanteperdrix wrote:
> Just to add another argument. I just asked a friend who is a
> professional sysadmin. He creates directory under /mnt and mount
> things under these directories. So, I am not sure the standard is
> even applied by the people who should use it.

Well being the admin, the admin can mount whatever they want in there.
That agrees with the standard just fine.

> If you read on the last site I sent, under the /media article: 
> 
> Amid much controversy and consternation on the part of system and
> network administrators a directory containing mount points for
> removable media has now been created. Funnily enough, it has been
> named /media.

The /media is generally used by auto mounters for removable media.

> Are you sure, 100% sure, that every Xenomai user expects to be able
> to use /mnt as a mount point? Or that they will create directories
> under /mnt like everybody has been doing since Linux exists?

I do use /mnt and I do NOT create directories in it.  I know people that
do create directories.  The admin can do whatever they want in there.

-- 
Len Sorensen

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Lennart Sorensen]

On Fri, Nov 28, 2014 at 10:50:38AM +0100, Gilles Chanteperdrix wrote:
> This is ridiculous. Because the standard changed, and one
> distribution, Debian, decided to follow the new standard, which
> seems to be not widely accepted, and even controversial, you want to
> impose what Debian does to everybody. The distribution I use has
> mount points under /mnt. So, why following Debian and not the
> distribution I use, and what sysadmin have been doing for ages?

Feel free to make xenomai mandate creating some new mountpoint somewhere
else for its use.

> You want the mount point to be somewhere else? Fine, put a symbolic
> link.
> 
> mkdir /run/xenomai
> ln -s /run/xenomai /mnt/xenomai

And when I do mount /dev/sdf1 /mnt, what will xenomai think?  It sure
won't like it.

Do NOT put xenomai stuff in /mnt.  If you do, some of us will have to
maintain permanent patches to fix xenomai and I hate doing that.

-- 
Len Sorensen

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Gilles Chanteperdrix]

On Fri, Nov 28, 2014 at 11:07:22AM -0500, Lennart Sorensen wrote:
> On Fri, Nov 28, 2014 at 12:15:27AM +0100, Gilles Chanteperdrix wrote:
> > Just to add another argument. I just asked a friend who is a
> > professional sysadmin. He creates directory under /mnt and mount
> > things under these directories. So, I am not sure the standard is
> > even applied by the people who should use it.
> 
> Well being the admin, the admin can mount whatever they want in there.
> That agrees with the standard just fine.
> 
> > If you read on the last site I sent, under the /media article: 
> > 
> > Amid much controversy and consternation on the part of system and
> > network administrators a directory containing mount points for
> > removable media has now been created. Funnily enough, it has been
> > named /media.
> 
> The /media is generally used by auto mounters for removable media.
> 
> > Are you sure, 100% sure, that every Xenomai user expects to be able
> > to use /mnt as a mount point? Or that they will create directories
> > under /mnt like everybody has been doing since Linux exists?
> 
> I do use /mnt and I do NOT create directories in it.  I know people that
> do create directories.  The admin can do whatever they want in there.

I understand the reasoning, but I like /mnt/xenomai

So, instead of imposing a mount point to everyone, I would suggest
to keep /mnt/xenomai as the documented default. And add an option to
the configure script, to allow users which absolutely want to adhere
to the FHS to choose another mount point.

-- 
					    Gilles.

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Lennart Sorensen]

On Fri, Nov 28, 2014 at 12:55:37PM +0100, Gilles Chanteperdrix wrote:
> Again, using /mnt/xenomai does not break any distribution following
> the standard.

Yes it does when I mount my disk on /mnt.  xenomai is hidden.

> Let us try things another way, the possibilities we have are:
> - /mnt/xenomai: a solution that used to be standard but ceased to be
> with the FHS which did not provide a standard replacement, but does
> not break any distribution

As above, it does.

> - /run/xenomai: a solution that relies on the existence on the /run
> directory, which is not standard, but is going to be, maybe.
> - /var/run/xenomai: a solution which does not violate any version of
> the standard, but is not standard either, does not make clear that
> the directory is a mount point (which /mnt does), breaks the
> existing documentation, breaks the existing usages of Xenomai 3, and
> is longer to type.

/ is a mount point too, but the name doesn't imply that either.  That's a
bad argument.

> So, I really find that /mnt/xenomai is the best compromise. There is
> no standard solution, at least /mnt/xenomai is a solution that used
> to be standard.

Well it will break on my system all the time.  It's a very shitty solution
and not a compromise at all.  You are breaking things on my system.

/mnt is for the admin's use only.  No exceptions.

-- 
Len Sorensen

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Lennart Sorensen]

On Fri, Nov 28, 2014 at 01:10:08PM +0100, Gilles Chanteperdrix wrote:
> I do not think it is. /mnt is off limit for distributions. Fine,
> xenomai can use it without any risk of breaking any distribution
> then.

Sure you are not breaking the distribution, just the life for the user
of the system.

-- 
Len Sorensen

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Lennart Sorensen]

On Fri, Nov 28, 2014 at 01:10:08PM +0100, Gilles Chanteperdrix wrote:
> I do not think it is. /mnt is off limit for distributions. Fine,
> xenomai can use it without any risk of breaking any distribution
> then.

As soon as xenomai is packaged, then it becomes part of the distribution
and hence can no longer even consider using /mnt.

-- 
Len Sorensen

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Gilles Chanteperdrix]

On Fri, Nov 28, 2014 at 11:13:10AM -0500, Lennart Sorensen wrote:
> On Fri, Nov 28, 2014 at 12:55:37PM +0100, Gilles Chanteperdrix wrote:
> > Again, using /mnt/xenomai does not break any distribution following
> > the standard.
> 
> Yes it does when I mount my disk on /mnt.  xenomai is hidden.

You choose to do that, not the distribution. Read my sentence again
"does not break any distribution following the standard".

> 
> > Let us try things another way, the possibilities we have are:
> > - /mnt/xenomai: a solution that used to be standard but ceased to be
> > with the FHS which did not provide a standard replacement, but does
> > not break any distribution
> 
> As above, it does.
> 
> > - /run/xenomai: a solution that relies on the existence on the /run
> > directory, which is not standard, but is going to be, maybe.
> > - /var/run/xenomai: a solution which does not violate any version of
> > the standard, but is not standard either, does not make clear that
> > the directory is a mount point (which /mnt does), breaks the
> > existing documentation, breaks the existing usages of Xenomai 3, and
> > is longer to type.
> 
> / is a mount point too, but the name doesn't imply that either.  That's a
> bad argument.
> 
> > So, I really find that /mnt/xenomai is the best compromise. There is
> > no standard solution, at least /mnt/xenomai is a solution that used
> > to be standard.
> 
> Well it will break on my system all the time.  It's a very shitty solution
> and not a compromise at all.  You are breaking things on my system.
> 
> /mnt is for the admin's use only.  No exceptions.

As you said, the admin chooses to use it as he wants. And 
mkdir /mnt/tmp
will allow you to have xenomai, and mount temporary filesystems as
well.

Just because you have chosen to use /mnt in an arguably stupid
despite standard way, should not influence how others want to use
it. 

-- 
					    Gilles.

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Lennart Sorensen]

On Fri, Nov 28, 2014 at 01:43:48PM +0100, Gilles Chanteperdrix wrote:
> The problem is not why not? The problem is why. A mount point was
> chosen, which is not stupid, documentation and web contents were
> written, people have started getting used to it. So, why changing it
> now ? So from my point of view, Jan patch looks like a patch that
> has been submitted without thinking to the consequences, and changes
> things for bad reasons.

The original choice of /mnt does not consider the consequences. 

> The sentence you quote does not really apply to xenomai, since
> xenomai is not an "installation program". The standard basically
> says that software installed by the distribution has no business
> messing with /mnt. But Xenomai is not installed by a distribution.
> If distibutions want to change this directory when they make xenomai
> their own package, they will apply patches, they do this all the
> time, and document the difference in
> /usr/share/doc/xenomai/README.Debian

Debian includes xenomai packages.  So yes it can be installed by a
distribution.

Make the mount point a configurable option (compile time is fine) so
at least when building packages for a distribution the location can be
changed to something sane.

-- 
Len Sorensen

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Lennart Sorensen]

On Fri, Nov 28, 2014 at 05:16:07PM +0100, Gilles Chanteperdrix wrote:
> You choose to do that, not the distribution. Read my sentence again
> "does not break any distribution following the standard".

So what?  Who cares if it breaks the distribution.  You are breaking
things for someone.

> As you said, the admin chooses to use it as he wants. And 
> mkdir /mnt/tmp
> will allow you to have xenomai, and mount temporary filesystems as
> well.

After doing it this way for 20 years I am highly unlikely to remember
to do that.

> Just because you have chosen to use /mnt in an arguably stupid
> despite standard way, should not influence how others want to use
> it. 

Well I don't tell others how to use it.  But don't make software that
forced me to change my use either.

-- 
Len Sorensen

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Lennart Sorensen]

On Fri, Nov 28, 2014 at 05:24:25PM +0100, Philippe Gerum wrote:
> Let's make this a configuration variable set by a build switch, and move
> on. Looking over the trenches, I don't think there will be any consensus
> on this anyway.

Exactly.  Both /run and /var/run seem sensible, but not necesarily fully
standard at this point.

-- 
Len Sorensen

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Lennart Sorensen]

On Fri, Nov 28, 2014 at 05:11:12PM +0100, Gilles Chanteperdrix wrote:
> I understand the reasoning, but I like /mnt/xenomai
> 
> So, instead of imposing a mount point to everyone, I would suggest
> to keep /mnt/xenomai as the documented default. And add an option to
> the configure script, to allow users which absolutely want to adhere
> to the FHS to choose another mount point.

Well anyone making a package for a distribution would have to change it
after all.

-- 
Len Sorensen

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Gilles Chanteperdrix]

On Fri, Nov 28, 2014 at 11:18:18AM -0500, Lennart Sorensen wrote:
> On Fri, Nov 28, 2014 at 01:43:48PM +0100, Gilles Chanteperdrix wrote:
> > The problem is not why not? The problem is why. A mount point was
> > chosen, which is not stupid, documentation and web contents were
> > written, people have started getting used to it. So, why changing it
> > now ? So from my point of view, Jan patch looks like a patch that
> > has been submitted without thinking to the consequences, and changes
> > things for bad reasons.
> 
> The original choice of /mnt does not consider the consequences. 
> 
> > The sentence you quote does not really apply to xenomai, since
> > xenomai is not an "installation program". The standard basically
> > says that software installed by the distribution has no business
> > messing with /mnt. But Xenomai is not installed by a distribution.
> > If distibutions want to change this directory when they make xenomai
> > their own package, they will apply patches, they do this all the
> > time, and document the difference in
> > /usr/share/doc/xenomai/README.Debian
> 
> Debian includes xenomai packages.  So yes it can be installed by a
> distribution.

the integration of the xenomai package into the Debian repositories
is largely a failed experiment. I think the problem is that the
debian xenomai package does not have enough users for them to look
hard enough and report bugs to reach a good package quality. And
there will never be enough users for that, because real-time is a
niche, whether people want it or not. So, our goal should be to
not cut users from the project, and try and keep them reporting
back to us instead of downstream distributions, and to work for
these users, not to try and work with intermediates.

> 
> Make the mount point a configurable option (compile time is fine) so
> at least when building packages for a distribution the location can be
> changed to something sane.

Ok, we agree at last, it seems.

-- 
					    Gilles.

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Philippe Gerum]

On 11/28/2014 05:09 PM, Lennart Sorensen wrote:
> On Fri, Nov 28, 2014 at 10:50:38AM +0100, Gilles Chanteperdrix wrote:
>> This is ridiculous. Because the standard changed, and one
>> distribution, Debian, decided to follow the new standard, which
>> seems to be not widely accepted, and even controversial, you want to
>> impose what Debian does to everybody. The distribution I use has
>> mount points under /mnt. So, why following Debian and not the
>> distribution I use, and what sysadmin have been doing for ages?
> 
> Feel free to make xenomai mandate creating some new mountpoint somewhere
> else for its use.
> 
>> You want the mount point to be somewhere else? Fine, put a symbolic
>> link.
>>
>> mkdir /run/xenomai
>> ln -s /run/xenomai /mnt/xenomai
> 
> And when I do mount /dev/sdf1 /mnt, what will xenomai think?  It sure
> won't like it.
> 
> Do NOT put xenomai stuff in /mnt.  If you do, some of us will have to
> maintain permanent patches to fix xenomai and I hate doing that.
> 

Let's make this a configuration variable set by a build switch, and move
on. Looking over the trenches, I don't think there will be any consensus
on this anyway.

-- 
Philippe.

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Lennart Sorensen]

On Fri, Nov 28, 2014 at 05:24:23PM +0100, Gilles Chanteperdrix wrote:
> the integration of the xenomai package into the Debian repositories
> is largely a failed experiment. I think the problem is that the
> debian xenomai package does not have enough users for them to look
> hard enough and report bugs to reach a good package quality. And
> there will never be enough users for that, because real-time is a
> niche, whether people want it or not. So, our goal should be to
> not cut users from the project, and try and keep them reporting
> back to us instead of downstream distributions, and to work for
> these users, not to try and work with intermediates.

Getting a kernel chosen in Debian for which there is a working
ipipe/xenomai patch is certainly a problem.

Still having the runtime be packaged is quite handy.

> Ok, we agree at last, it seems.

Absolutely.  Don't want thousands of build time options, but a few are
certainly useful at times.  If there was an obvious right choice for
the mount it ought to be used, but there isn't.

So far everyone just knows what the wrong places are, with no right
places yet.

-- 
Len Sorensen

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Gilles Chanteperdrix]

On Fri, Nov 28, 2014 at 11:29:19AM -0500, Lennart Sorensen wrote:
> On Fri, Nov 28, 2014 at 05:24:23PM +0100, Gilles Chanteperdrix wrote:
> > the integration of the xenomai package into the Debian repositories
> > is largely a failed experiment. I think the problem is that the
> > debian xenomai package does not have enough users for them to look
> > hard enough and report bugs to reach a good package quality. And
> > there will never be enough users for that, because real-time is a
> > niche, whether people want it or not. So, our goal should be to
> > not cut users from the project, and try and keep them reporting
> > back to us instead of downstream distributions, and to work for
> > these users, not to try and work with intermediates.
> 
> Getting a kernel chosen in Debian for which there is a working
> ipipe/xenomai patch is certainly a problem.
> 
> Still having the runtime be packaged is quite handy.

It would be handy if the runtime package was built correctly, but
since you were the first one to use the word "shitty", if there one
thing shitty it is Debian's debian/rules. This file has essentially
been unmaintained for years, just modified enough to compile the
next version, without taking the release notes into account, and
removing options or compilation flags that were no longer useful.
The method to provide patches for the kernel has disappeared from
make-kpkg around Lenny or something. But since no user was paying
attention, nobody noticed.

No, really, stay away from Debian's xenomai packages.

-- 
					    Gilles.

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Gilles Chanteperdrix]

On Fri, Nov 28, 2014 at 11:29:19AM -0500, Lennart Sorensen wrote:
> On Fri, Nov 28, 2014 at 05:24:23PM +0100, Gilles Chanteperdrix wrote:
> > the integration of the xenomai package into the Debian repositories
> > is largely a failed experiment. I think the problem is that the
> > debian xenomai package does not have enough users for them to look
> > hard enough and report bugs to reach a good package quality. And
> > there will never be enough users for that, because real-time is a
> > niche, whether people want it or not. So, our goal should be to
> > not cut users from the project, and try and keep them reporting
> > back to us instead of downstream distributions, and to work for
> > these users, not to try and work with intermediates.
> 
> Getting a kernel chosen in Debian for which there is a working
> ipipe/xenomai patch is certainly a problem.

As soon as you start patching the kernel, it does not really make
sense to absolutely pick the same kernel version as Debian, you can
just as well compile a mainline version with a Debian-like
modularized configuration. Actually, I provided exactly that for one
version of Xenomai, but the amount of downloads was ridiculous, so I
do not believe this is what users are after, either.



-- 
					    Gilles.

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Lennart Sorensen]

On Fri, Nov 28, 2014 at 05:35:03PM +0100, Gilles Chanteperdrix wrote:
> It would be handy if the runtime package was built correctly, but
> since you were the first one to use the word "shitty", if there one
> thing shitty it is Debian's debian/rules. This file has essentially
> been unmaintained for years, just modified enough to compile the
> next version, without taking the release notes into account, and
> removing options or compilation flags that were no longer useful.
> The method to provide patches for the kernel has disappeared from
> make-kpkg around Lenny or something. But since no user was paying
> attention, nobody noticed.

Well the debian rules in the xenomai git tree seem pretty decent these
days at least in the xenomai-2.6 tree.  The addition of the -dbg package
generation a few months ago was so nice.

> No, really, stay away from Debian's xenomai packages.

The one actually in Debian, yeah it's not much use anymore.  I have
stopped looking for help from that one.

-- 
Len Sorensen

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Lennart Sorensen]

On Fri, Nov 28, 2014 at 05:40:56PM +0100, Gilles Chanteperdrix wrote:
> As soon as you start patching the kernel, it does not really make
> sense to absolutely pick the same kernel version as Debian, you can
> just as well compile a mainline version with a Debian-like
> modularized configuration. Actually, I provided exactly that for one
> version of Xenomai, but the amount of downloads was ridiculous, so I
> do not believe this is what users are after, either.

Ridiculously low I am guessing?

-- 
Len Sorensen

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Gilles Chanteperdrix]

On Fri, Nov 28, 2014 at 11:44:39AM -0500, Lennart Sorensen wrote:
> On Fri, Nov 28, 2014 at 05:35:03PM +0100, Gilles Chanteperdrix wrote:
> > It would be handy if the runtime package was built correctly, but
> > since you were the first one to use the word "shitty", if there one
> > thing shitty it is Debian's debian/rules. This file has essentially
> > been unmaintained for years, just modified enough to compile the
> > next version, without taking the release notes into account, and
> > removing options or compilation flags that were no longer useful.
> > The method to provide patches for the kernel has disappeared from
> > make-kpkg around Lenny or something. But since no user was paying
> > attention, nobody noticed.
> 
> Well the debian rules in the xenomai git tree seem pretty decent these
> days at least in the xenomai-2.6 tree.  The addition of the -dbg package
> generation a few months ago was so nice.

Well, yes, because at some point, we had a look at it and started
fixing it.

-- 
					    Gilles.

Re: [Xenomai] [pull] forge: Adjust default registry mount point

[Gilles Chanteperdrix]

On Fri, Nov 28, 2014 at 11:45:49AM -0500, Lennart Sorensen wrote:
> On Fri, Nov 28, 2014 at 05:40:56PM +0100, Gilles Chanteperdrix wrote:
> > As soon as you start patching the kernel, it does not really make
> > sense to absolutely pick the same kernel version as Debian, you can
> > just as well compile a mainline version with a Debian-like
> > modularized configuration. Actually, I provided exactly that for one
> > version of Xenomai, but the amount of downloads was ridiculous, so I
> > do not believe this is what users are after, either.
> 
> Ridiculously low I am guessing?

Yes, something like 10 downloads, probably including the tests I did
on my side.

-- 
					    Gilles.